1. Field of the Invention
The present invention relates to mechanical slot machines for amusement. More particularly, the invention relates to mechanical slot machines which are worked by springs and have no electric motor, electromagnets or the like and which, by a simple operation of pulling an actuating lever forward, automatically rotate for a period a plurality of rotatable drums bearing pictures, symbols, etc., on their peripheries, automatically stop the rotatable drums in regular sequence and at intervals, and automatically discharge coins according to the combinations of pictures, symbols, etc., arranged horizontally.
2. Description of the Prior Art
Drum-type slot machines designed to discharge coins according to the combinations of pictures, symbols, etc., shown on the peripheries of a plurality of rotatable drums have been widely known. Most of them have been electrically driven slot machines using an electric motor to rotate the drums and electromagnets to stop them. Because these electrically driven slot machines need not only the electric motor and electromagnets but also a battery or other power source, they have had large and complicated mechanisms and have been expensive.
Therefore, a number of mechanical slot machines which rotate drums by utilizing mechanical energy, such as the force of springs and which have no electric motor or electromagnets, have been disclosed as found in U.S. Pat. Nos. 4,097,048, 4,037,845 and 3,565,441. However, these mechanical slot machines have been either complicated in mechanism and not easy to operate or, on the contrary, too simple in construction to perform such function as makes the game exciting. For instance, some of the former have had stop buttons, one for each drum, to stop drums which have been rotated by means of an actuating lever. These have had the disadvantage that they require several manual operations from the starting of the drums to the stopping of the drums and therefore make the game complicated. On the other hand, some of the latter have been designed to stop the drums automatically by a stopper incorporated therein, not by stop buttons. Because slot machines of this kind stop a plurality of drums simultaneously in a relatively short time and cannot stop them one by one at intervals, they have had a disadvantage that the arrangement of pictures, symbols, etc., on the drums, when stopped, is liable to show a certain pattern or tendency and therefore the fairness of the game is not maintained.